The present invention relates to a method whereby the carboxyl groups on an organic compound may be converted to methylol groups, for example, a method of converting adipic acid to 1,6-hexanediol. In various industrial processes it is necessary to convert a compound containing a carboxyl group to the corresponding primary alcohol; however, at the present time on really efficient processes have been developed for accomplishing such. For example, in the production of 1,6-hexanediol from adipic acid, the most popular method for accomplishing such is to first esterify the adipic acid with an alcohol and then hydrogenolyze the ester to obtain a product comprising 1,6-hexanediol and the alcohol utilized in the esterification. Obviously, a direct route from the acid to the alcohol would be more desirable than one involving the formation of an intermediate. Processes have been developed whereby a carboxyl compound may be converted to the corresponding hydroxyl compound but such processes have been found to be substantially inefficient and uneconomical because of low conversions and other process problems. Examples of prior art include U.S. Pat. No. 3,344,196 issued Sept. 26, 1967 to Hubert Corr, et al., and the article by H. Smith Broadbent, et al., "Rhenium and its Compounds as Hydrogenation Catalysts. III. Rhenium Heptoxide," Journal of Organic Chemistry, Vol. 24, P. 1847 (1959).
It is thus an object of the present invention to provide a process whereby an organic compound containing carboxyl groups may be efficiently processed to convert such groups directly to methylol (--CH.sub.3 OH) groups without the necessity of the formation of any intermediates. It is a particular object of the present invention to provide a process whereby alkanoic monocarboxylic and dicarboxylic acids may be converted directly to the corresponding alcohols or diols with good efficiency. Additional objects will become apparent from the following description of the present invention.